Novel scoring system for determining fetal candidacy for prenatal intervention for severe congenital lower urinary tract obstruction

Objectives: To evaluate a novel scoring system that combines several prenatal parameters for selecting ideal candidates for fetal intervention, and for predicting postnatal survival in patients with severe fetal lower urinary tract obstruction (LUTO). Methods: We retrospectively reviewed all cases of severe LUTO evaluated for fetal intervention in a single large fetal center between January 2013 and December 2017. A scoring system for determining fetal candidacy for intervention was retrospectively developed based on postnatal outcomes. The proposed scoring system included fetal urinary biochemistry, renal ultrasound parameters, initial bladder volume, and degree of bladder refill. Relevant demographic characteristics, ultrasound reports and laboratory results were reviewed. Receiver operating characteristic (ROC) curves were used to select the cut-off values for initial bladder volume and degree of bladder refill and to evaluate the performance of the scoring system in predicting postnatal death. Results: Of the 79 LUTO patients evaluated, 31 were eligible for the study. The overall 6-month postnatal survival was 64.5 % (20/31). A scoring system (0−8) was suggested with 2 points for unfavorable biochemistry, 4 points for ultrasound evidence of dysplastic kidneys, 1 point for inadequate initial bladder volume and 1 point for inadequate bladder refill. Scores>3 (N = 7) were associated with 0 % 6-month survival. The ROC curve for predicting postnatal mortality showed area under curve (AUC) of 0.82 (95 % CI 0.65−0.99). Subgroup analysis within subjects who underwent fetal intervention (N = 22) also confirmed the significance of the distribution of the scoring system between groups who survived and those who did not after adjustment for GA at delivery (p = 0.01). Conclusion: We propose a novel scoring system for antenatal evaluation of patients with severe LUTO which may be useful in selecting those candidates most appropriate for intervention and in counseling parents about predicted postnatal outcome.